In 2012, Brazilian entrepreneur Eike Batista was on top of the world: Forbes had ranked him the seventh richest man on the planet, and the wealthiest Brazilian overall with a net worth topping $30 billion. He was named as one of TIME’s most influential people in the world, with Eduardo Paes, the mayor of Rio de Janeiro, praising him. Batista’s “most valuable asset is his commitment to Rio’s legacy,” Paes wrote at the time.

Unfortunately for Batista it’s looking more and more like this might be literally true. Since landing on the TIME 100 list less than two years ago, Batista has watched as his $30 billion in wealth has vanished to anywhere from $200 million to possibly nothing at all if you factor in debt. How does something like this happen?

Batista’s wealth was always tied up in the valuation of his commodities businesses, the most important of which was an oil and gas exploration company, OGX, he founded in 2007. The company was launched during one of the most robust periods of economic growth in Brazil‘s history and during a period off all-time highs in the price of oil. Since that time, economic growth has slowed from 7.5% in 2010 to less than 1% last year. Oil prices have also come down, making many of the deep-water wells OGX was betting on economically unfeasible. But most importantly, the wells that he did get up in running just never ended up producing the kind of oil he’d promised investors. According to a report in Bloomberg Businessweek:

“Batista predicted that OGX would pump 50,000 barrels a day by the end of 2012, ramping up to 730,000 a day by 2015. He said it was one of a group of “bonanza assets” worth as much as $1.5 trillion that would produce such high profit margins that they were “idiot-proof.” When OGX began pumping oil in January 2012, Batista bragged on Twitter that the two-year interval between discovery and production was a world record. The wells were far less bountiful than he’d hoped, however, and the company is now producing fewer than 17,000 barrels a day.”

Shares in Batista’s company fell more than 90%, and OGX’s failure sent shock waves through his other ventures, many of which were created to capitalize on his oil company’s success. Another of Batista’s companies, for instance, manufactured deep-sea oil rigs, and depended on OGX for its business.

Since the collapse of OGX’s stock price midway through this year, Batista has been selling off assets in the hope of keeping his core oil business afloat. But the battle over OGX debt has turned into a global free-for-all with investors around the world clamoring for Batista’s assets for fear that a potential bankruptcy would them out in the cold. Batista has not been speaking with the media of late, but gave a rare interview published in today’s Wall Street Journal in which he vowed that his comeback was already in the works.

In the interview Batista is contrite, arguing that while he lost investors money, nobody lost more than he. “I am the biggest loser in this. I tried to create wealth for all of us. That was the reason we raised all the money—to create wealth and share it,” Batista said.

Still, the 57-year old entrepreneur believes he can hold his creditors at bay and maintain control of his flagship oil company. With billions in debt outstanding held by investors across the globe, it will be a long and drawn out fight. But with $30 billion already down the drain, how much more does Batista have to lose?